gnulib

http://www.gnu.org/software/gnulib/
Gnulib is intended to be the canonical source for most of the important "portability" and/or common files for GNU projects. These are files intended to be shared at the source level; Gnulib is not a library meant to be installed and linked against. Unlike most projects, Gnulib does not normally generate a source tarball distribution; instead, developers should just grab modules directly from the repository. While portability across operating systems is not one of GNU's primary goals, it has helped introduce many people to the GNU system, and is worthwhile when it can be achieved at a low cost. This collection helps lower that cost.

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